Inverted telephoto projection lenses

ABSTRACT

An improved inverted telephoto lens having a seven element positive group separated from a two element negative group.

0R anew-1; I

United States KH O Q H Lechner INVERTED TELEPHOTO PROJECTION LENSES Inventor: Hadrian B. Lechner, North Chili,

Assignee: Bausch & Lomb Incorporated,

Rochester, NY.

Filed: Feb. 11, 1972 Appl. No.: 225,493

U.S. Cl ..350/2l4, 350/175 ML Int. Cl. ..G02b 9/64 Field of Search ..350/2 14 3,719;'4l3 451 March 6,1973

[56] Relerences Cited UNITED STATES PATENTS 3,551,013! [2/1970 Grey ..350/2l4 3,656,839 4/1972 Trotta ..350/2l4 Primary Examiner-John K. Corbin Attorney-F rank C. Parker et al.

[57] ABSTRACT An improved inverted telephoto lens having a seven element positive group separated from a two element negative group.

3 Claims, 1 Drawing Figure INVERTED TELEPIIO'IO PROJECTION LENSES BACKGROUND OF THE INVENTION The lens of my invention is an improvement on that disclosed in US. Pat. No. 3,551,031 to D8. Grey in that the first seven elements of that design have been retained substantially intact to effect an important saving in manufacturing while at the same time permitting entirely different ends to be achieved.

SUMMARY OF THE INVENTION Like the above mentioned design my lens includes a first negative element which is preferably a planoconcave lens I followed by a relatively thick planoconvex lens ll. Lenses III, IV and V constitute a group which are respectively biconvex, biconcave and biconvex.

These in turn are followed by a biconvex lens VI and a negative meniscus lens VII concave toward the short conjugate. Each of the lenses I-VII are airspaced, none of them being in mutual contact.

A wide space separates lens VIl from lens VIII, said space being the characteristic wide separation of the positive group from the negative group in inverted telephoto lenses, lenses W" and IX constituting the negative group. Lens VIII is a negative meniscus concave toward the short conjugate and lens IX is a biconvex lens of relatively wide aperture. Lenses VIII and IX are somewhat widely airspaced from one another.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a schematic optical diagram of the lens.

DESCRIPTION OF THE PREFERRED EMBODIMENT The preferred lens provides an image resolution of approximately 5 lines per millimeter on a suitable projection screen at a magnification of 90X, a projection half-angle of 14, and a relative aperture .of f/ 1.6, this corresponding to 450 lines per millimeter in the object plane. The lens is well corrected for both the chromatic and non-chromatic aberrations. The individual ele-' ments are fabricated with relatively shallow radii which renders the lens relatively easy to manufacture. This fact also permits an optimum sharing of the corrective functions among the various elements.

Although optical glass of very fine quality is specified, the glasses chosen are of moderate cost. The lens is additionally designed for a relatively simple alignment procedure and the design is conveniently tolerant of slight variations in alignment.

The lens is designed to work with a standard cover glass in the object conjugate.

The construction data for my lens design are given in Table l below wherein the'radii R, thicknesses t, and spaces S are given in ratio to the focal length of the lens taken as unity, each value being subnumerated in increasing sequence from the short conjugate toward the long. The radii are taken as centered on the short conjugate side of the lens, the short conjugate side being TABLE I S Q 1, 0.930] R, w r, 0.454] U R. l.890f I. 0.328 R, 1.890 1, 0.195 1v 1t, 3.853] r, 0.116 R. 4.184 1. 0.526] v 11,. 3.771 5, 0.0191 a,, 3.469] 5, 0.143 W 11,, 6.398] S 0006 I! 6.298] s, 0.060 a... 0.972] s, 0.216 v11! 1a,. 18.537] s, 3.636] R., 26.801 s. 1.349 or R 6.257] 6,, 1.720 I, 29.3 n L691 v, 54.3 n l.69l v, 54.8 n. L720 v. 29.3 n, 1.69! v; 54.8 n 1.69] v 54.8 '1. 1.720 M, 29.3 71,. 1.517 v, 64.5 n,- 1.720 v, 46.0

It is within the contemplation of optical manufacturing methods that slight variations in the above construction values may be tolerated with the understanding that by certain well known practices, skilled optical technicians will be able to assemble and adjust the overall lens to a useful performance level, although possibly to somewhat less than ideal standards. Such variations would be regarded as tolerable if they were to fall within the ranges of values listed in Table ll below:

TABLE II 1.552 R, 1.555] 199 R, 100 R 100 1.269 R, 1.275 32.99 R, 35.26] L885] R, 1.893] 1.886] R, 1.392 3.333 R, 3.1172 4.163 R, 4.201 3.753 R,, 3.787] 3.457 -R,, 3.482 6.351 R,, 6.444] 3.576 R., 3.602 6.246 R,, 6.345 0.971] R,, 0.973] 17.8] R,, 20 25.8] R,, 28] 6.234] n,. 6.272] 0.343] r, 0.372] 0.1395 1,

0.435] 0471! a plano convex lens ll, convex toward said long con- 0.186] 1, 0.202 03 If 0319f ugate, spaced S, from sa1d lens I, hav1ng R R 1 0.314 1, 0.340] n and 1 8:33 g fggf a biconvex lens lll spaced S, from said lens ll,- having 0.504 1. 0.547 5 R R t n and v 1 3-33; a biconcave lens lV, spaced S;, from said lens lll, hav- I 4 0.005 s, 0.009] g 1 8, '4, "m and 0172] 4 0176! a biconvex lens V, spaced S from said lens lV, hav- 0.054 s, 0.066 0.218 8 m R101! "D5 and "6 3.630] 3.240 a biconvex lens Vl, spaced S, from said lens V, hav- 1. 6 1.3??? 1.725 mg Rm Rm and v6 1.689] n,,,2 1.693 a negative meniscus lens Vll concave toward said 1.689 11, 1.693 L7 I 8 nls L722 short con ugate spaced 8,, from sa1d lens Vl, havmg 1.689 n,,, 1.693 13, 14 1, "m and '1, {2*}: 612 1-693 a negative meniscus lens Vlll, concave toward said short conjugate, spaced 8, from said lens Vll, hav- 1.718 n 1.722 mg R R n v and i 25 a biconvex lens IX spaced S, from said lens VIll, hav- 52.8 v 56:8 in 11, R18: o "as and '0; 3 20 g said values falling within the ranges given in the table 52.8 v, 56.8 below 52.8 v, 56.8 27.3 u 31.3 62.5 11-,, 66.5

1.552] R 1.555 44.0 u8 48.0 m0! Hoof 131m :1 :18 l. The inverted telephoto lens having long and short 5 con ugates comprlsmg nine mutually airspaced ele- 1.885] R, 1.893] ments which are, beginning on the short conjugate side, gigs; 25; 33; a plano concave lens I concave to the short conjugate 4.163 -R, 4.201 f side, a plano convex lens ll convex to the long conju- 30 jfg 312;; gate side, a biconvex lens lll, a biconcave lens IV, a 11 6:444] biconvex lens V, another biconvex lens V], a negative 1 2211: 2?! meniscus lens Vll concave to the short conjugate side, P 2 said aforementioned lenses forming a positive group, 17.8] R,, 20] and 25.8 R,, 28

6.234] R,,, 6.272 another negat1ve menlscus lens Vlll concave to the 0.343 1, 0372] short conjugate side, and a biconvex lens [X the 833;! 2'': 8-3;?! last two mentioned lenses comprising a negative 2 group widely airspaced from said positive group 0.311] 1, 0.319] and having construction data substantially as fol- 40 gig; 333 3 lows; 0.103] 1,, 0.128 wherein the radii R, thicknesses t, and spaces S are 832 3-332; ratioed to the overall focal length f of the lens; j M negative radii are centered toward the long conju- 1 0009f ate and the refractive indices n and dis ersions 45 (M72! (76f g 1 D P 0.054 s 0.066 v, as well as the other values, are subnumerated m- 0.214] s, 0.2 1 8f 3.630] s 3.640] creaslng toward the long con ugate. L336! z 1361f 1.718 n,,, 1.722 (1972 I 0 1 7 1.689 n L693 v111 f a f 1.689 n: 1.693 R 18.537 1 0.526 L718 m L721 .41: 2 0- 3 49 1.689 n L693 x 1.689 n 1.693 R" 57 L718 n 1.722 n 1.517 V v, 64.5 in: n

27.3 vf" 31.3 52.8 v, 56.8 2. An inverted telephoto lens havmg long and short 52.8 v 56.8 conjugates comprising nine mutually airspaced eleu 4 5 ments descnbed by radn, R, thicknesses t, refractive m- 52.8 v, 56.8 dices n dispersions v, and separated by spaces S, said d S f l f 60 62.5 v, 66.5 R, I, an values be1ng ratlos of the ocal ength f o 440 4&0 sa1d lens, sa1d fadll being taken' as negat1ve 1f centered I toward said conjugate and all f Said values being 3. The lens of claim 2 having the following values: subnumerated mcreasmg toward sa1d long conjugate, sa1d elements bemg defined 1n order toward said long RI 1554] n 0359! con ugate as: 1

a plano concave lens I, concave toward said short 2; Z 8:332;

conjugate. having R R,, t,, n and 11,; 1| 4 

1. The inverted telephoto lens having long and short conjugates comprising nine mutually airspaced elements which are, beginning on the short conjugate side, a plano concave lens I concave to the short conjugate side, a plano convex lens II convex to the long conjugate side, a biconvex lens III, a biconcave lens IV, a biconvex lens V, another biconvex lens VI, a negative meniscus lens VII concave to the short conjugate side, said aforementioned lenses forming a positive group, and another negative meniscus lens VIII concave to the short conjugate side, and a biconvex lens IX the last two mentioned lenses comprising a negative group widely airspaced from said positive group and having construction data substantially as follows; wherein the radii R, thicknesses t, and spaces S are ratioed to the overall focal length f of the lens; negative radii are centered toward the long conjugate; and the refractive indices nD and dispersions Nu , as well as the other values, are subnumerated increasing toward the long conjugate: R15 0.972f t8 0.116f VIII R16 18.537f t9 0.526f -R17 26.801f S8 1.349f IX R18 6.257f nD8 1.517 Nu 8 64.5nD9 1.720 Nu 9 46.0
 1. The inverted telephoto lens having long and short conjugates comprising nine mutually airspaced elements which are, beginning on the short conjugate side, a plano concave lens I concave to the short conjugate side, a plano convex lens II convex to the long conjugate side, a biconvex lens III, a biconcave lens IV, a biconvex lens V, another biconvex lens VI, a negative meniscus lens VII concave to the short conjugate side, said aforementioned lenses forming a positive group, and another negative meniscus lens VIII concave to the short conjugate side, and a biconvex lens IX the last two mentioned lenses comprising a negative group widely airspaced from said positive group and having construction data substantially as follows; wherein the radii R, thicknesses t, and spaces S are ratioed to the overall focal length f of the lens; negative radii are centered toward the long conjugate; and the refractive indices nD and dispersions Nu , as well as the other values, are subnumerated increasing toward the long conjugate: R15 0.972f t8 0.116f VIII R16 18.537f t9 0.526f -R17 26.801f S8 1.349f IX R18 6.257f nD8 1.517 Nu 8 64.5nD9 1.720 Nu 9 46.0
 2. An inverted telephoto lens having long and short conjugates comprising nine mutually airspaced elements described by radii, R, thicknesses t, refractive indices nD, dispersions Nu , and separated by spaces S, said R, t, and S values being ratios of the focal length f of said lens, said radii being taken as negative if centered toward said long conjugate and all of said values being subnumerated increasing toward said long conjugate, said elements being defined in order toward said long conjugate as: a plano concave lens I, concave toward said short conjugate, having R1, R2, t1, nD1 and Nu 1; a plano convex lens II, convex toward said long conjugate, spaced S1 from said lens I, having R3, R4, t2, nD2 and Nu 2; a biconvex lens III spaced S2 from said lens II, having R5, R6, t3, nD3 and Nu 3; a biconcave lens IV, spaced S3 from said lens III, having R7, R8, t4, nD4 and Nu 4; a biconvex lens V, spaced S4 from said lens IV, having R9, R10, t5, nD5 and Nu 5; a biconvex lens VI, spaced S5 from said lens V, having R11, R12, t6, nD6 and Nu 6; a negative meniscus lens VII concave toward said short conjugate spaced S6 from said lens VI, having R13, R14, t7, nD7 and Nu 7; a negative meniscus lens VIII, concave toward said short conjugate, spaced S7 from said lens VII, having R15, R16, t8, nD8 Nu 8; and a biconvex lens IX spaced S8 from said lens VIII, having R17, R18, t9, nD9 and Nu 9; said values falling within the ranges given in the table below: 1.552f <R1<1.555f 100f <R2<-100f 100f <R3<-100f 1.269f <R4<1.275f 32.99f <R5<35.26f 1.885f <R6<1.893f 1.886f <R7<1.892f 3.833f <-R8<3.872f 4.163f <-R9<4.201f 3.753f <R10<3.787f 3.457f <-R11<3.482f 6.351f <R12<6.444f 3.576f <R13<3.602f 6.246f <R14<6.345f .971f <R15<0.973f 17.8f <R16<20f 25.8f <-R17<28f 6.234f <R18<6.272f 0.343f <t1<0.372f 0.895f <t2<0.970f 0.435f <t3<0.471f 0.186f <t4<0.202f 0.311f <t5<0.319f 0.314f <t6<0.340f 0.187f <t7<0.203f 0.103f <t8<0.128f 0.504f <t9<0.547f 0.017f <S1<0.022f 0.141f <S2<0.144f 0.005f <S3<0.009f 0.172f <S4<0.176f 0.054f <S5<0.066f 0.214f <S6<0.218f 3.630f <S7<3.640f 1.336f <S8<1.361f 1.718 <nD1<1.722 1.689 <nD2<1.693 1.689 <nD3<1.693 1.718 <nD4<1.722 1.689 <nD5<1.693 1.689 <nD6<1.693 1.718 <nD7<1.722 1.515 <nD8<1.519 1.718 <nD9<1.722 27.3 < Nu 1<31.3 52.8 < Nu 2<56.8 52.8 < Nu 3<56.8 27.3 < Nu 4<31.3 52.8 < Nu 5<56.8 52.8 < Nu 6<56.8 27.3 < Nu 7<31.3 62.5 < Nu 8<66.5 44.0 < Nu 9<48.0 